Electric valve control device and electric valve device

Abstract

An electric valve control device is configured to (i) start inputting pulse to a stepping motor to rotate a rotor in a first direction, (ii) obtain a rotation angle of the rotor based on a rotation angle signal and a position of the rotor based on a magnetic-flux-density signal each time pulse is input to the stepping motor, and (iii) stop inputting pulse when a change in the rotation angle of the rotor matches a change pattern information and a position of the rotor is a proximity position or a position nearer a reference position than is the proximity position. The change pattern information includes a change in the rotation angle indicating rotation in a second direction.

The invention claimed is: 
     
         1 . An electric valve control device for controlling an electric valve including a valve body that has a valve port, a stepping motor that includes a rotor, a valve member that moves toward the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, and a stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is at a reference position,
 the electric valve control device comprising:   a rotation angle sensor that outputs a signal corresponding to a rotation angle of the rotor; and   a position sensor that outputs a signal corresponding to a position of the rotor,   wherein   (i) the electric valve control device is configured to start inputting a pulse to the stepping motor to rotate the rotor in the first direction,   (ii) the electric valve control device is configured to obtain the rotation angle of the rotor based on the signal of the rotation angle sensor and the position of the rotor based on the signal of the position sensor each time the pulse is input to the stepping motor, and   (iii) the electric valve control device is configured to stop inputting the pulse to the stepping motor when a change in the rotation angle matches a change pattern that is predetermined and the position of the rotor is a proximity position that is predetermined or a position nearer the reference position than is the proximity position, and   wherein the change pattern includes a change in the rotation angle indicating rotation in the second direction.   
     
     
         2 . The electric valve control device according to  claim 1 ,
 wherein the change pattern further includes a change in the rotation angle indicating the rotation in the first direction.   
     
     
         3 . The electric valve control device according to  claim 1 ,
 wherein the change pattern includes changes in the rotation angle corresponding to multiple pulses repeatedly input to the stepping motor in a predetermined order.   
     
     
         4 . The electric valve control device according to  claim 3 ,
 wherein the electric valve control device is configured to obtain, in an operation to set the change pattern, rotation angles corresponding to the multiple pulses and set the change pattern based on the rotation angles when the change in the rotation angle indicating the rotation in the second direction is detected while the pulse is input to the stepping motor to rotate the rotor in the first direction.   
     
     
         5 . The electric valve control device according to  claim 1 ,
 wherein the electric valve includes a permanent magnet mounted on the rotor, and   wherein the rotation angle sensor outputs a signal corresponding to a rotation angle of a magnetic field generated by the permanent magnet.   
     
     
         6 . The electric valve control device according to  claim 1 ,
 wherein the electric valve includes a permanent magnet mounted on the rotor,   wherein the rotor moves toward the valve port when the rotor rotates in the first direction and moves away from the valve port when the rotor rotates in the second direction,   wherein the rotation angle sensor outputs a signal corresponding to a rotation angle of a magnetic field generated by the permanent magnet, and   wherein the position sensor outputs a signal corresponding to a strength of the magnetic field generated by the permanent magnet.   
     
     
         7 . An electric valve device comprising:
 the electric valve; and   the electric valve control device according to  claim 1 .   
     
     
         8 . An electric valve control device for controlling an electric valve including a valve body that has a valve port, a stepping motor that includes a rotor, a valve member that moves toward the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, and a stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is at a reference position,
 the electric valve control device comprising:   a rotation angle sensor that outputs a signal corresponding to a rotation angle of the rotor; and   a position sensor that outputs a signal corresponding to a position of the rotor,   wherein   (i) the electric valve control device is configured to start inputting a pulse to the stepping motor to rotate the rotor in the first direction,   (ii) the electric valve control device is configured to obtain the rotation angle of the rotor based on the signal of the rotation angle sensor and the position of the rotor based on the signal of the position sensor each time the pulse is input to the stepping motor, and   (iii-1) the electric valve control device is configured to stop inputting the pulse to the stepping motor when a change in the rotation angle indicating rotation in the second direction is detected and the position of the rotor is a proximity position that is predetermined or a position nearer the reference position than is the proximity position, or (iii-2) the electric valve control device is configured to stop inputting the pulse to the stepping motor when a change in the rotation angle indicating the rotation in the first direction is detected after the change in the rotation angle indicating the rotation in the second direction is detected and the position of the rotor is the proximity position or the position nearer the reference position than is the proximity position.   
     
     
         9 . An electric valve control device for controlling an electric valve including a valve body that has a valve port, a stepping motor that includes a rotor, a valve member that moves toward the valve port when the rotor rotates in a first direction and moves away from the valve port when the rotor rotates in a second direction, and a stopper mechanism that restricts rotation of the rotor in the first direction when the rotor is at a reference position,
 the electric valve control device comprising:   a rotation angle sensor that outputs a signal corresponding to a rotation angle of the rotor, the signal being a rotation angle signal; and   a position sensor that outputs a signal corresponding to a position of the rotor, the signal being a position signal,   wherein   (i) the electric valve control device is configured to start inputting a pulse to the stepping motor to rotate the rotor in the first direction,   (ii) the electric valve control device is configured to obtain the rotation angle signal and the position signal, and   (iii-1) the electric valve control device is configured to stop inputting the pulse to the stepping motor when a change in the rotation angle signal indicating rotation in the second direction is detected and the position signal has a value corresponding to a proximity position that is predetermined or a position nearer the reference position than is the proximity position, or (iii-2) the electric valve control device is configured to stop inputting the pulse to the stepping motor when a change in the rotation angle signal indicating the rotation in the first direction is detected after the change in the rotation angle signal indicating the rotation in the second direction is detected and the position signal has the value corresponding to the proximity position or the position nearer the reference position than is the proximity position.